The invention relates to a media discharge device, like for flowable media such as gaseous, powdery, liquid, pasty and/or similar media, which can be conveyed and expelled by pressurization or with the aid of a delivery flow including a second medium.
Highly-viscous media, such as creamy, pasty or other media which are non-flowable or only viscously flowable under their own weight and which may be free of alcoholic solvents or the like permit dispensing in small quantities only with great difficulty when e.g. the nozzle passage discharge to the environment has a width of less than two, one or half a millimeter or when the medium needs to be dispensed atomized from the dispenser. To facilitate discharge a second pump can be used to convey an aggregate or carrier medium, applied to the first medium in the outlet duct of the unit or directly at the inlet end of the nozzle end duct. In this arrangement the second medium, for example air, is delivered to the environment expediently in a volume many times higher but at a pressure many times lower than that of the first medium together therewith through the medium orifice or nozzle passage.
For optimum dosed discharge, media differing in particular in their viscosity require dispensers or pump units having differing performance features. Especially the ratio defined by each unit of travel or velocity of the pumping stroke relative to the delivery volumes and the delivery pressures of the two pumping units that needs to be adapted to the flow properties of the medium in each case. For this purpose it may be sufficient to vary the performance features of only one of the two pumping units by a differing design configuration or to leave out this pumping unit completely, whilst the other pumping unit is permanently formed by the same pump which is preassembled ready for operation prior to being connected to the second pumping unit. This is to be understood that this pump comprises in the prefabricated condition two pumping units guided precisely against each other for producing the pressure in a pump chamber. In the case of a plunger pump this involves a pump body and a plunger unit slidable therein, guided at two locations located axially spaced away from each other free of tilt and diametral clearance at or exclusively within the pump body.
Accordingly, by actuating a plunger guided in this way such a pump may also be used to discharge the medium from the pump chamber through the plunger and, where necessary, subsequently suctioned from a reservoir into the pump chamber if the pump is not combined with a pressurizing chamber of the second pump. If for this purpose only one plunger having the shape of a flat ring and having sealing lips, secured directly to the pump body of the first pump is omitted the design in supporting this plunger becomes relatively complicated.
Furthermore, in this arrangement the inner width of the discharge head to be arranged on the plunger and requiring manual actuation always needs to remain the same should the discharge head need to tightly clasp the outer circumference of the first pump body.